Casing scraper



Feb. 10, 1953 a. M. sclvALLY CASING SCRAPER Filed 'Feb. 18. 1950 lll ATTORNEY Patented Feb. 10, 1953 UNITED STATES PATENT OFFICE CASIN G SCRAPER Bernice M. Scivally, Houston, Tex.

Application February 18, 1950, Serial No. 145,001 claims. (c1. 16s- 18) This invention relates to a casing scraper, and more particularly to a tool adapted to be inserted in a well casing for scraping the inside of the same.

The invention has for its chief object the provision of a scraping device adapted for attachment to the lower end of a string of drill pipe whereby the same may be lowered into the casing for smoothing and conditioning the inside thereof.

Another object of the invention is to provide a casing scraping tool capable of being inserted in a string of drill pipe to follow the cutting bit, for the purpose of scraping off cement left inside the casing from 'a previous cementing operation,

and removing burrs resulting from perforation shots.

Another object is the construction of a casing scraping device which is effective for removing material coating the inside of the casing either by upward or downward movement of the device in the casing or by rotation of the same therein.

A further object is to provide a casing scrap-ing device having scraper blades moveable radially outwardly of the body of the tool for engagement with the material being removed, and having means operated by the pressure of iuid in the drill pipe for moving the blades outwardly and maintaining the same in extended condition.

A still further object is the construction of a well scraping device having scraper means formed to assist in the removal from the well of material scraped from the casing during operation of the device.

The invention, briefly stated, comprises a tubular body adapted for attachment to the lower end of a drill pipe and having means for the attachment thereto of a cutting bit, said body having slots therethrough with scraping blades moveably positioned in the slots and pressure responsive means inside the body for moving the blades outwardly through the slots.

The invention will best be understood from the following description, constituting a specification of the same, when taken in conjunction with the annexed drawings, wherein Figure 1 is an elevational view of the invention partly broken away and partly in section, showing the device inserted in a well casing and indicating the relationship between the various parts;

Figure 1A is a fragmentary view partly broken away and partly in section showing the invention with a cutting bit attached thereto as used in drilling out a cemented well;

Figure 2 is a fragmentary view on a somewhat enlarged scale, of a portion `of the scraping tool, partly broken away to indicate the interior structure of the same; and

Figure 3 is a cross-sectional View taken along the line 3-3 of Figure 2, looking in the direction indicated by the arrows.

The invention as illustrated in Figures l and 1A is shown in -position for operation in a weil, the surrounding earth formation of which is indicated at 2, wherein a casing 4 is positioned. The casing 4 in the present instance is shown as having perfo-rations 6 therein, which perforations and the well have been sealed by cement 8 or other suitable material.

Referring to the drawings in greater detail, the

body of the scraping tool indicated at l0 is of. generally cylindrical shape having its upper end internally threaded at l2 to receive the lower end of a threaded coupling hi by which the tool is attached to the lower end of the drill pipe It.

gated slots, and being in circumferentially over- 1 lapping relation.

Scraping blades 26 of somewhat smaller crosssectional area than the openings 2li project through the openings for radial movement outwardly of the body, each of these blades being provided with a backing plate 28 disposed within the body. The backing plates 28 may, if desired, be of such a size and shape as to formk when assembled a complete 4helix in the shape of asubstantially continuous cylinder lining the interior of the body from end to end thereof between the threaded portions kI 2 and I8.

Within the body in engagement with the backing plates, a yieldable element 3!) is loosely positioned which element may take the form of a flexible tube of rubber or the like, adapted to operate under the iniiuence of pressure in the drill p-ipe to move the blades outwardly through the slots. ends with the lips 32 which seat against the end surfaces 32 of the couplings l2 and 2 lto form fluid sealing engagement therewith when the yieldable element is expanded by internal pressure.`

A plug 34 may be threaded into the coupling I8 inside the body of the tool, which. plug provides,

a restricted passage 36 at the bottom of the yieldable element 30', to increase the pressure of fluid in the body sufciently to maintain the blades in textended condition during the operation of the The outer ends of the blades 25 are preferably somewhat rounded as indicated at 38, and the upper edges of the blades may be of hardened The yieldable element is formed at its metal or provided with a heat-treated metal facing 4B of Haynes Stellite or the like.

In the operation of the invention, the apparatus assembled in the manner shown in Figures 1 and 2, with the tool attached to the lower end of the drill pipe and the cutting bit attached to the lower end of the tool is in condition for inserting in the well. The introduction of pressure fluid into the drill pip-e then results in exp-anding the yieldable element clue to the restricted pas,- sage, and the scraping blades are moved radially outwardly of the body. The device in this condition may be lowered and pushed down into the casing so that the scraping blades engage and scrape oli" material on the inside of the casing. Rotation of the drill then results in an upward spiral or helical scraping action of the blades.

It will be noted that the helical arrangement of the scraping blades produces an upward movement of any material scraped by the blades from the inside of the casing. Moreover, due to th-e spacing of the blades the drilling' mud or fluid may pass freely between the same, and any material such as cement, steel, burrs or other cuttings produced by the cutting bit may be borne upwardly therewith.

It will also be apparent that the scraping blades extend entirely about the periphery of the tool so that they will perform a cutting action when the drill pipe is raised or lowered as well t as when it is rotated.

rihe diameter of the tool with the scraping blades fully extended is preferably somewhat less than the internal diameter oi' the well casing, so

that the casing wili not be damaged by con- 2v tinued use of the tool, but the latter will effectively smooth and condition the inside of the casing. It will thus be seen that the invention as described above provides a well scraping tool of simple design and rugged construction capable of withstanding the hard wear and long usager to which such a device is likely to be subjected.

While the invention has been disclosed in connection with a particular embodiment of the same, it is to be understood that this is for the purpose of illustration only, and numerous changes and modifications can be made in the various parts without departing from the spirit of the invention or the scope of the appended claims.

Having thus clearly shown and described the invention what is claimed las new and desired to secure by Letters Patent is:

1. In a well scraping device adapted to be positioned in the bore of a well, a cylindrical body member having a passage for the flow of uid therethrough, a plurality of spaced openings in said member h-elically arranged about the same, scraper means movably disposed in said openings and terminating inwardly or" the member, and a tubular element of resilient material in said member in engagement with said scraper means and responsive to the pressure of fluid in said passage for urging said scraper means outwardly through said openings.

:2. In a well scraping device adapted to be inserted in e, well casing and operable by vertical movement and rotation therein to scrape the inside or" said casing, a cylindrical body member having a passage for the flow of iluid theretln'ough, and a plurality of elongated openings helically disposed in overlapping relation entirely about the periphery of said member, scraper means movably disposed in said openings and extending inwardly of said member and a tubular element of resilient material in the member in engagement with said scraper means and responsive to the pressure of fluid in said passage for moving said scraper means outwardly of said member.

3. In a well scraping device adapted to be positioned in the bore of a well -a cylindrical body member having a passage for the flow of fluid therethrough and a plurality of elongated, vertically-spaced openings helically disposed in overlapping relation about its periphery, scraper means disposed in each of said openings for movement outwardly of said member, a curved backing plate on each of said scraper means inside said member, the inner surfaces of said plates forming a substantially continuous cylindrical surface, a tubular element of resilient material in said member in yielding engagement with said cylindrical surface and responsive to the pressure of fluid in said passage to hold said scraper means in extended condition.

4. In a well scraping device adapted tobe positioned in the bore of a well, a cylindrical body member having a passage for the flow of iiuid therethrough, coupling means at the ends of said member for connecting the member into a drill pipe, said member having a plurality of spaced openings therein, scraper means movably disposed in said openings, curved backing plates on said scraper means in said member and forming therein a substantially continuous cylinder, a tubular element of resilient material in said member in yielding engagement with said cylinder and said coupling means said element being expansible under the influence of fluid in said member into sealing engagement with said couplings and to hold said scraper means in extended condition.

5. In a well scraping device adapted to be positioned in the bore of a well, a cylindrical body member having a passage for the flow of duid therethrough, coupling means at the ends of said member for connecting th-e member into a drill pipe, said member having a plurality of longitudinally spaced openings therein, scraper means movably disposed in the openings and extending outwardly of the body and whose outer extremities are formed with edge portions which are offset around the circumference of the tube so that they cover the entire horizontal projection of the circumference of the tube, a tubular element of resilient material in said member in yielding engagement with said scraper means and expansible undel` the influence of the pressure of fluid in said member to hold said scraper means in extended condition, and means at the ends of said element sealingly engageable with said couplings when said element is expanded.

BERNICE M. SCIVALLY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,432,649 Wessels Oct. 17, 1922 2,117,836 Brown May 17, 1938 2,224,412 Smith Dec. 10, 1940 2,334,788 OLeary Nov. 23, 1943 2,438,673 McMahan Mar. 30, 1948 2,447,966 Stephens Aug. 24, 1948 2,453,199 Crall Nov. 9, 1948 2,464,390 Hammer Mar. 15, 1949 

